Ablation catheter

ABSTRACT

Devices, systems and methods are disclosed for the mapping of electrical signals and the ablation of tissue. Embodiments include an ablation catheter that has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be transformed from a compact, linear configuration to a helical configuration, such as to map and ablate pulmonary vein ostia.

STATEMENT OF RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/692,416, filed Jun. 20, 2005, entitled“Pulmonary Vein Ablation Devices,” which is incorporated by referenceherein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to catheters and methods forperforming targeted tissue ablation in a subject. In particular, thepresent invention provides devices comprising catheters having distalends configured to pulmonary vein ostia, and methods for treatingconditions (e.g., cardiac arrhythmias) with these and similar devices.

BACKGROUND OF THE INVENTION

Tissue ablation is used in numerous medical procedures to treat apatient. Ablation can be performed to remove undesired tissue such ascancer cells. Ablation procedures may also involve the modification ofthe tissue without removal, such as to stop electrical propagationthrough the tissue in patients with an arrhythmia. Often the ablation isperformed by passing energy, such as electrical energy, through one ormore electrodes causing the tissue in contact with the electrodes toheats up to an ablative temperature. Ablation procedures can beperformed on patients with atrial fibrillation by ablating tissue in theheart.

Mammalian organ function typically occurs through the transmission ofelectrical impulses from one tissue to another. A disturbance of suchelectrical transmission may lead to organ malfunction. One particulararea where electrical impulse transmission is critical for proper organfunction is in the heart. Normal sinus rhythm of the heart begins withthe sinus node generating an electrical impulse that is propagateduniformly across the right and left atria to the atrioventricular node.Atrial contraction leads to the pumping of blood into the ventricles ina manner synchronous with the pulse.

Atrial fibrillation refers to a type of cardiac arrhythmia where thereis disorganized electrical conduction in the atria causing rapiduncoordinated contractions that result in ineffective pumping of bloodinto the ventricle and a lack of synchrony. During atrial fibrillation,the atrioventricular node receives electrical impulses from numerouslocations throughout the atria instead of only from the sinus node. Thisoverwhelms the atrioventricular node into producing an irregular andrapid heartbeat. As a result, blood pools in the atria that increases arisk for blood clot formation. The major risk factors for atrialfibrillation include age, coronary artery disease, rheumatic heartdisease, hypertension, diabetes, and thyrotoxicosis. Atrial fibrillationaffects 7% of the population over age 65.

Atrial fibrillation treatment options are limited. Lifestyle change onlyassists individuals with lifestyle related atrial fibrillation.Medication therapy assists only in the management of atrial fibrillationsymptoms, may present side effects more dangerous than atrialfibrillation, and fail to cure atrial fibrillation. Electricalcardioversion often restores sinus rhythm, but has a high recurrencerate. In addition, if there is a blood clot in the atria, cardioversionmay cause the clot to leave the heart and travel to the brain or to someother part of the body, which may lead to stroke. What are needed arenew methods for treating atrial fibrillation and other conditionsinvolving disorganized electrical conduction.

Various ablation techniques have been proposed to treat atrialfibrillation, including the Cox-Maze procedure, linear ablation ofvarious regions of the atrium, and circumferential ablation of pulmonaryvein ostia. The Cox-Maze procedure and linear ablation procedures aretedious and time-consuming, taking several hours to accomplish.Pulmonary vein ostial ablation is proving to be difficult to do, and hasresulted in inadequate results and unacceptable trauma to the pulmonaryveins. There is therefore a need for improved atrial ablation productsand techniques.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, an ablation catheter foran operator to treat a patient with an arrhythmia is disclosed. Thecatheter includes an elongate, flexible tubular body member have aproximal end, a distal end and a lumen therebetween. The catheterfurther includes a control shaft, coaxially disposed and slidinglyreceived with the lumen of the tubular body member. A flexible carrierassembly is attached to the end of the control shaft and includes atleast one ablation and/or mapping elements. Retraction of the controlshaft causes the carrier assembly to transition from a compact, nearlinear configuration, to a helix or partial helix. In a preferredembodiment, the helix is less than 360°.

In a preferred embodiment, the carrier assembly can be withdrawn into alocation within the tubular body member. In another preferredembodiment, the ablation catheter includes at least two carrierassemblies that can be transitioned between a compact, near linearconfiguration to a helix or partial helix. In yet another preferredembodiment, the catheter can be placed over a guidewire or includes anintegral guidewire tip.

According to another aspect of the invention, an ablation catheter foran operator to treat a patient with an arrhythmia is disclosed. Thecatheter includes an elongate, flexible tubular body member have aproximal end, a distal end and a lumen therebetween. The catheterfurther includes a control shaft, coaxially disposed and slidinglyreceived with the lumen of the tubular body member. A flexible carrierassembly is attached to the end of the control shaft and includes atleast one ablation and/or mapping elements in an umbrella tipconfiguration. Retraction of the control shaft causes the carrierassembly to change shape, such as to conform to tissue surrounding oneor more pulmonary veins entering the left atrium of a patient.

In a preferred embodiment, the ablation catheter includes a secondcarrier assembly, also in an umbrella tip configuration. In anotherpreferred embodiment, the catheter includes an anchoring element, suchas a balloon or expandable cage, for stabilizing and/or anchoring theablation catheter in a pulmonary vein. In yet another preferredembodiment, the catheter includes an ultrasound element for directingultrasound energy in a circular pattern toward tissue. In yet anotherpreferred embodiment, one or more carrier arms of the umbrella tip canbe rotated, stabilized, or otherwise manipulated to better conform to orstabilize with tissue such as pulmonary vein ostial tissue. In yetanother preferred embodiment, the catheter can be placed over aguidewire or includes an integral guidewire tip. In yet anotherpreferred embodiment, the catheter includes an advancable spline whichcan be used to position or stabilize the carrier assembly.

According to yet another aspect of the invention, an ablation catheterfor an operator to treat a patient with an arrhythmia is disclosed. Thecatheter includes an elongate, flexible tubular body member have aproximal end, a distal end and a lumen therebetween. The catheterfurther includes a flexible carrier assembly comprising an inflatableballoon with mounted or embedded ablation and/or mapping elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various embodiments of thepresent invention, and, together with the description, serve to explainthe principles of the invention. In the drawings:

FIG. 1 illustrates a side sectional view of an ablation catheter,consistent with present invention, with the distal end inserted into apulmonary vein of a patient.

FIGS. 2 a and 2 b illustrates a perspective view of the distal portionof the ablation catheter of FIG. 1, consistent with the presentinvention.

FIG. 3 illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which thedevice includes a proximal energy delivering carrier assembly and adistal mapping carrier assembly.

FIG. 4 illustrates an ablation catheter handle consistent with thepresent invention including the dual carrier assemblies of FIG. 3.

FIG. 5 illustrates a side sectional view of an ablation catheter,consistent with present invention, with the distal end inserted into apulmonary vein of a patient.

FIG. 6 illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which thecarrier assembly includes one or more carrier arms that can berotationally positioned.

FIG. 7 illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which asleeve can be advanced to manipulate one or more carrier arms of thecarrier assembly, and the distal end includes a flexible wire forinserting into a pulmonary vein.

FIG. 8 a illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which one ormore carrier arms of the carrier assembly are maintained in closeproximity with a collar.

FIG. 8 b is an end view of the ablation catheter of FIG. 8 a.

FIG. 8 c is an end view of the collar of the ablation catheter of FIG. 8a.

FIG. 9 illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which thecarrier assembly includes a radially deployable spline that can bedeployed in between two carrier arms.

FIGS. 9 a and 9 b illustrate a side view of the distal portion of theablation catheter of FIG. 9 a, with the spline in partially and fullydeployed conditions, respectively, with the carrier arms removed forclarity.

FIG. 10 illustrates a perspective view of the distal portion of anablation catheter consistent with the present invention, in which thecarrier assembly comprises a balloon with fixedly mounted ablationelements.

FIG. 11 illustrates a side view of the distal portion of the ablationcatheter of FIG. 10.

FIG. 12 a illustrates a perspective view of an ablation catheterconsistent with the present invention, wherein the carrier assemblycomprises a single carrier arm and the carrier assembly is in thedeployed state.

FIG. 12 b illustrates a perspective view of a distal portion of theablation catheter of FIG. 12 a, in which the carrier assembly is in afully compacted state.

FIG. 12 c illustrates a perspective view of a distal portion of theablation catheter of FIG. 12 b, in which the carrier assembly is in apartially deployed state.

FIG. 13 illustrates a distal portion of an ablation catheter consistentwith the present invention, in which the carrier assembly comprises asingle carrier arm whose distal end is attached along a different axisthan the proximal end.

FIG. 13 a illustrates a side view of a distal portion of the catheter ofFIG. 13.

FIG. 13 b illustrates a perspective view of a distal portion of thecatheter of FIG. 13.

FIG. 14 illustrates a side sectional view of a distal portion of anablation catheter consistent with the present invention, in which thecarrier assembly comprises a single carrier arm.

FIG. 15 a illustrates a perspective view of a proximal portion of anablation catheter consistent with the present invention, including ahandle with multiple controls.

FIG. 15 b illustrates a perspective view of a distal portion of theablation catheter of FIG. 15 a, in which the carrier assembly comprisesa single carrier arm and the carrier assembly is in a fully compactedstate.

FIG. 15 c illustrates a perspective view of a distal portion of theablation catheter of FIG. 15 a, in which the carrier assembly comprisesa single carrier arm and the carrier assembly is in the fully deployedstate.

FIG. 15 d illustrates the ablation catheter of FIGS. 15 a through 15 cafter having been placed through a transeptal sheath and the carrierassembly deployed and contacting the ostium of the left superiorpulmonary vein.

FIG. 16 illustrates a perspective view of an ablation catheterconsistent with the present invention, including a first deployablecarrier assembly and a second deployable carrier assembly.

FIG. 16 a illustrates an end view of the ablation catheter of FIG. 16.

FIG. 16 b illustrates a side sectional view of the distal portion of theablation catheter of FIG. 16, wherein the distal carrier assembly is incontact with the lumen of a pulmonary vein and the proximal carrierassembly is in contact with the pulmonary vein ostium.

FIG. 17 illustrates a side view of an ablation catheter consistent withthe present invention, including a carrier assembly comprising a singlecarrier arm that can be fully retracted within a lumen of the shaft ofthe device.

FIG. 17 a illustrates a side sectional view of the device of FIG. 17wherein the carrier assembly has been fully deployed.

FIG. 17 b illustrates a side sectional view of the device of FIG. 17wherein the carrier assembly has been fully compacted.

FIG. 17 c illustrates an end view of the device of FIG. 17 a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

The present invention provides catheters for performing targeted tissueablation in a subject. In preferred embodiments, the catheters comprisea tubular body member having a proximal end and distal end andpreferably a lumen extending therebetween. The catheter is preferably ofthe type used for performing intracardiac procedures, typically beingpercutaneously introduced and advanced from the femoral vein in apatient's leg. Alternative methods involve percutaneous introductioninto the jugular vein of the patient's neck, or other anatomical entrypoint that can be used to access the target location within the patient.The catheter is preferably introducable through a sheath and alsopreferably is advancable over a guidewire. The catheter preferably has asteerable tip that allows precise positioning of the distal portion suchas when the distal end of the catheter needs to access a pulmonary veinof the left atrium of the patient's heart. The catheters includeablation elements mounted on one or more carrier arms of a flexiblecarrier assembly. Typical metals chosen for carrier assemblyconstruction include but are not limited to: stainless steel, Nitinol,Elgiloy™, other alloys and combinations thereof. These ablation elementscan be used to ablate and/or map electrical activity of tissue. Thecarrier assembly is attached to a control shaft that is coaxiallydisposed and slidingly received within the lumen of the tubular bodymember. The shape of the carrier assembly is adjusted by advancing orretracting the control shaft, such as to engage one or more ablationelements against cardiac tissue, typically pulmonary vein ostial tissue.

Arrays of ablation elements, preferably geometrically-adjustableelectrode arrays, may be configured in a wide variety of ways andpatterns. In particular, the present invention provides devices withmulti-dimensional electrode arrays that provide electrical energy, suchas radiofrequency (RF) energy, in monopolar (unipolar), bipolar orcombined monopolar-bipolar fashion, as well as methods for treatingconditions (e.g., atrial fibrillation, supra ventricular tachycardia,atrial tachycardia, ventricular tachycardia, ventricular fibrillation,and the like) with these devices. Alternative to or in combination withablation elements that deliver electrical energy to tissue, other formsand types of energy can be delivered including but not limited to: soundenergy such as acoustic energy and ultrasound energy; electromagneticenergy such as electrical, magnetic, microwave and radiofrequencyenergies; thermal energy such as heat and cryogenic energies; chemicalenergy such as energy generated by delivery of a drug; light energy suchas infrared and visible light energies; mechanical and physical energy;radiation; and combinations thereof.

As described above, the normal functioning of the heart relies on properelectrical impulse generation and transmission. In certain heartdiseases (e.g., atrial fibrillation) proper electrical generation andtransmission are disrupted or are otherwise abnormal. In order todiagnose and/or prevent improper impulse generation and transmissionfrom causing an undesired condition, the ablation catheters of thepresent invention may be employed.

One current method of treating cardiac arrhythmias is with catheterablation therapy. Physicians make use of catheters to gain access intointerior regions of the body. Catheters with attached electrode arraysor other ablating devices are used to create lesions that disruptelectrical pathways in cardiac tissue. In the treatment of cardiacarrhythmias, a specific area of cardiac tissue having aberrantconductive pathways, such as atrial rotors, emitting or conductingerratic electrical impulses, is initially localized. A user (e.g., aphysician) directs a catheter through a main vein or artery into theinterior region of the heart that is to be treated. The ablating elementor elements are next placed near the targeted cardiac tissue that is tobe ablated, such as a pulmonary vein ostium. After performing anelectrical mapping procedure, the physician directs energy, provided bya source external to the patient, from one or more ablation elements toablate the neighboring tissue and form a lesion. In general, the goal ofcatheter ablation therapy is to disrupt the electrical pathways incardiac tissue to stop the emission of and/or prevent the propagation oferratic electric impulses, thereby curing the heart of the disorder. Fortreatment of atrial fibrillation, currently available methods anddevices have shown only limited success and/or employ devices that areextremely difficult to use or otherwise impractical.

The ablation catheters of the present invention allow the generation oflesions of appropriate size and shape to treat conditions involvingdisorganized electrical conduction (e.g., atrial fibrillation). Thecreated lesions are segmented and localized. The lesions may be linearor curvilinear, circumferential and partial circumferential, and/orcontinuous or discontinuous. The ablation catheters of the presentinvention are also practical in terms of ease-of-use and limiting riskto the patient, as well as significantly reducing procedure times. Thelesions created by the ablation catheters are suitable for inhibitingthe propagation of inappropriate electrical impulses in the heart forprevention of reentrant arrhythmias.

The catheters of the present invention can perform tissue ablationand/or mapping of electrical signals present in tissue. Patients, suchas those with atrial fibrillation, are diagnosed and treated with theherein described mapping and/or ablation procedures. The catheters ofthe present invention are specifically applicable to mapping andablation of the pulmonary vein ostia located in the left atrium of thepatient's heart. These vein ostia are approximately 1.5 cm in diameterand often are non-circular in geometry, especially when a venousbifurcation is present proximate the ostia. The carrier assembly of thepresent invention may include one or more carrier arms that areconfigured to conform to these circular and non-circular contours ofpulmonary vein ostia. One or more carrier arms, or groups of carrierarms, may be configured to be independently advancable and retractable,such as to properly engage pulmonary vein ostium tissue. The carrierarms are preferably made of Nitinol, and may have round, oval,triangular, rectangular, or trapezoidal cross-sectional geometry. Thecarrier arms may include compound splines or angles, such as to conformto pulmonary vein ostia and surrounding tissue. Each carrier arm mayinclude one or more sensors, such as temperature sensors integral to anablation element or mounted between two ablation elements, such as tomeasure tissue temperature and/or blood temperature. In a preferredembodiment, a temperature sensor is mounted to a carrier arm in alocation more distal than the most distal ablation element, when thecarrier assembly is in a deployed, ready to deliver ablation energy,configuration. Information recorded by the temperature sensor can beused by an energy delivery unit of the present invention as a thresholdto avoid overheating of blood or tissue, as well as regulate power to atarget temperature. A first carrier arm may have a different propertythan a second carrier arm, such as a different rigidity, a differentnumber of ablation elements, or a different configuration of sensorssuch as temperature sensors.

The catheters of the present invention may be configured to be advancedinto the heart of a patient over a previously placed guidewire, such asa standard interventional 0.035″ guidewire. The catheter may include aninner lumen for the majority of its length, through which the guidewireis inserted, or the catheter may include a relatively short sidecar nearits distal end, where the guidewire inserted through a lumen of thesidecar. The placement over the guidewire allows simplified positioningand re-positioning by an operator. The guidewire placement also providesstability such as to simplify maintaining the position of the catheterduring energy delivery, typically 60 seconds.

The catheters of the present invention are configured to be insertedthrough the lumen of a previously placed transeptal sheath, such as a9.5 French (Fr) steerable transeptal sheath. The catheter of the presentinvention preferably include an integral steering mechanism, such as oneor more pull wires fixedly attached near a distal portion of thecatheter and operably attached to a lever, knob or other controlintegral to a handle of the catheter. The steering can be used todeflect the carrier assembly and distal end of the catheter into theleft and right pulmonary veins of the left atrium. The integral cathetersteering can be used in conjunction a steerable transeptal sheath.Multiple pull wires can be fixedly mounted 90° apart at separatedlocations in a distal portion of the catheter to provide multi-axis,precision controlled steering. The tubular body member of the ablationcatheter is constructed with sufficient columnar strength and rigidityto allow an operator to apply significant torque to the proximal endthat equivalently translates to the catheters distal portions.

The present invention includes one or more systems that include theablation catheters of the present invention. The system may furtherinclude a guide catheter such as a steerable transeptal sheath thatslidingly receives the ablation catheter. The system may further includean energy delivery unit, such as a unit configured to deliver RF and/orother forms of energy to the ablation elements of the catheter. Thesystem may further include a mapping unit that receives informationrecorded from one or more sensors of the ablation catheter, such as anablation element of the ablation catheter. The mapping unit provideselectrical activity information to an operator of the system. Themapping unit may be integral to the energy delivery unit.

Definitions. To Facilitate an Understanding of the Invention, a Numberof Terms are Defined Below.

As used herein, the terms “subject” and “patient” refer to any animal,such as a mammal like livestock, pets, and preferably a human. Specificexamples of “subjects” and “patients” include, but are not limited, toindividuals requiring medical assistance, and in particular, requiringatrial fibrillation catheter ablation treatment.

As used herein, the terms “catheter ablation” or “ablation procedures”or “ablation therapy,” and like terms, refer to what is generally knownas tissue destruction procedures. Ablation is often used in treatingseveral medical conditions, including abnormal heart rhythms. It can beperformed both surgically and non-surgically. Non-surgical ablation istypically performed in a special lab called the electrophysiology (EP)laboratory. During this non-surgical procedure a catheter is insertedinto the heart using fluoroscopy for visualization, and then an energydelivery apparatus is used to direct energy to the heart muscle. Thisenergy either “disconnects” or “isolates” the pathway of the abnormalrhythm (depending on the type of ablation). It can also be used todisconnect the conductive pathway between the upper chambers (atria) andthe lower chambers (ventricles) of the heart. For individuals requiringheart surgery, ablation can be performed during coronary artery bypassor valve surgery.

As used herein, the term “ablation element” refers to an energy deliveryelement, such as an electrode for delivering electrical energy such asRF energy. Ablation elements can be configured to deliver multiple typesof energy, such as ultrasound energy and cryogenic energy, eithersimultaneously or serially. Electrodes can be constructed of aconductive plate, wire coil, or other means of conducting electricalenergy through contacting tissue. Electrodes may comprise a laminateconstruction, such as at least one conductive layer and at least oneinsulative layer. RF electrodes preferably are constructed of platinumor a combination of platinum and iridium. In monopolar energy delivery,the energy is conducted from the electrode, through the tissue to aground pad, such as a conductive pad attached to the back of thepatient. The high concentration of energy at the electrode site causeslocalized tissue ablation. In bipolar energy delivery, the energy isconducted from a first electrode to one or more separate electrodes,relatively local to the first electrode, through the tissue between theassociated electrodes. Bipolar energy delivery results in more precise,shallow lesions while monopolar delivery results in deeper lesions. Bothmonopolar and bipolar delivery provide advantages, and the combinationof their use is a preferred embodiment of this application. Energy canalso be delivered using pulse width modulated drive signals, well knownto those of skill in the art. Energy can also be delivered in a closedloop fashion, such as a system with temperature feedback wherein thetemperature modifies the type, frequency and or magnitude of the energydelivered. Ablation elements may have one or more different shapes, suchas tubular electrodes mounted around a shaft such as a carrier arm, andother cross-sections such as oval, triangular, rectangular andtrapezoidal. Triangular cross sections can be positioned where multiplesides contact tissue for increased energy transfer or multiple sidescontact a cooling source such as blood for increased cooling. Theablation elements may include a heat-sinking element, such as aprojecting fin or other increased surface area portion. The ablationelements preferably include an integral temperature sensor, such as athermocouple comprised of copper and constantan wires that are weldedinside a mid portion of an RF electrode. In a preferred embodiment, anablation element can also be used to record and map electrical activityin tissue. In an alternative embodiment, one or more ablation elementsmay be configured to only map electrical activity, and not be configuredto deliver energy.

As used herein, the term “carrier assembly” refers to a flexiblecarrier, on which one or more ablation elements are disposed. Carrierassemblies include one or more carrier arms. Carrier assemblies are notlimited to any particular size, or shape, and can be configured to be inexpanded and unexpanded or compact states.

As used herein, the term “carrier arm” refers to a wire-like shaftcapable of interfacing with electrodes and a control shaft. A carrierarm is not limited to any size or measurement. Examples include, but arenot limited to: stainless steel shafts; Nitinol shafts; titanium shafts;polyurethane shafts; nylon shafts; and steel shafts. Carrier arms can beentirely flexible, or may include flexible and rigid segments.

As used herein, the term “spiral tip” refers to a carrier assemblyconfigured in its fully expanded state into the shape of a helix orspiral. The spiral tip is not limited in the number of spirals it maycontain. Examples include, but are not limited to, a wire tip body withone spiral, two spirals, ten spirals, and a half of a spiral. Thespirals can lie in a relatively single plane, or in multiple planes. Aspiral tip may be configured for energy delivery during an ablationprocedure.

As used herein, the term “lesion,” or “ablation lesion,” and like terms,refers to tissue that has received ablation therapy. Examples include,but are not limited to, scars, scabs, dead tissue, burned tissue andtissue with conductive pathways that have been made highly resistive ordisconnected.

As used herein the term “umbrella tip” refers to a carrier assembly witha geometric center which lies at a point along the axis of the distalportion of the tubular body member, with one or more bendable or hingedcarrier arms extending from the geometric center, in an umbrellaconfiguration. Each carrier arm may include one or more ablationelements. Each carrier arm of an umbrella tip includes a proximal armsegment and a distal arm segment, the distal arm segment more distalthan the proximal arm segment when the carrier assembly is in a fullyexpanded condition. One or more additional carrier arms can be includedwhich include no ablation elements, such as carrier arms used to providesupport or cause a particular deflection. An umbrella tip body is notlimited to any particular size. An umbrella tip may be configured forenergy delivery during an ablation procedure.

As used herein, the term “carrier arm bend point” refers to a joint(e.g., junction, flexion point) located on a carrier arm. The degree offlexion for a carrier arm bend point may range from 0 to 360 degrees.The bend portion can be manufactured such what when the carrier assemblyis fully expanded the bend point is positioned in a relatively straightportion, a curved portion, or in a discrete transition from a firstdirection to a second transition, such as a 45 degree bend transition.The bend portion can include one or more flexing means such as a spring,a reduced diameter segment, or a segment of increased flexibility.

As used herein, the term “energy delivery unit” refers to a deviceconfigured to operably attach to an ablation catheter and deliver one ormore forms of energy to an ablation element. The energy delivery unitincludes a user interface which allows an operator to make one or moresettings involved in applying the ablative energy. The energy unit maybe further configured to receive temperature information from theablation catheter. The temperature information can provided to anoperator and/or be used to provide closed loop energy delivery. Theenergy delivery unit may include a remote control device that may bemaintained in the sterile field of the patient during the ablationprocedure. The energy delivery unit may receive a signal from anoperator control integral to the ablation catheter that initiatesdelivery of the ablation energy.

As used herein, the term “mapping unit” refers to a device configured tooperably attach to an ablation catheter and receive one or more mappingsignals from an ablation element or other sensor of an ablationcatheter.

The present invention provides structures that embody aspects of theablation catheter. The present invention also provides tissue ablationsystems and methods for using such ablation systems. The illustrated andpreferred embodiments discuss these structures and techniques in thecontext of catheter-based cardiac ablation. These structures, systems,and techniques are well suited for use in the field of cardiac ablation.

However, it should be appreciated that the invention is applicable foruse in other tissue ablation applications such as tumor ablationprocedures. For example, the various aspects of the invention haveapplication in procedures for ablating tissue in the prostrate, brain,gall bladder, uterus, and other regions of the body, preferably regionswith an accessible wall or flat tissue surface, using systems that arenot necessarily catheter-based.

The multifunctional catheters of the present invention have advantagesover previous prior art devices. FIGS. 1-17 show various preferredembodiments of the multifunctional catheters of the present invention.The present invention is not limited to these particular configurations.

FIG. 1 illustrates a preferred embodiment of an ablation catheter of thepresent invention with an umbrella tip, wherein a carrier assemblyincludes multiple carrier arms configured to properly engage a pulmonaryvein ostium. Ablation catheter 50, and the other catheter devices ofthis application, are constructed of biocompatible materials suitablefor percutaneous advancement through the vasculature of a patient, andfor navigation within the patient's heart. Various tubular body membersand shafts are constructed of extruded materials such as Pebax,silicones, polyurethanes, polymers, elastomers, flexible plastics andcombinations of these. Ablation catheter 50 includes a distal tip 94,which is made of materials to be atraumatic to tissue and which is shownentering the lumen of pulmonary vein 15 such as to provide a stabilizingand/or anchoring function. Ablation catheter 50 further includes outershaft 76 that preferably has a diameter between 8 and 9 Fr and isconstructed to provide sufficient stability and torque through theprocedure. Ablation catheter 50 includes a carrier assembly of thepresent invention, carrier assembly 85, which includes multiple ablationelements 92 mounted to distal carrier arms 88.

The ablation elements 92 and other components of carrier assembly 85 areconfigured to flex to conform to pulmonary vein ostia and otherapplicable tissues. Outer shaft 76 can be advanced forward to change theshape of carrier assembly 85 and cause one or more ablation elements 92to contact tissue. Outer shaft 76 slidingly receives inner shaft 78,which is fixedly attached to proximal carrier arms 86. Distal carrierarms 88 are fixedly attached to cap 15 and the distal end of controlshaft 84. Proximal carrier arms 86 are pivotally attached to distalcarrier arms 88, such that advancement and retraction of control shaft84 relative to inner tube 78 causes the diameter of carrier assembly 85to contract and expand respectively, such as to cause the carrierassembly to expand to a 4-5 mm diameter. Inner shaft 78 further providescolumnar strength to allow an operator to advance inner shaft 78 andcause carrier assembly 85 to properly contact tissue, such as to conformto non-circular pulmonary vein ostia. Inner shaft 78 preferably isattached to a pull wire (not shown), near its distal end, which isoperably connected to a control on the proximal end of device 50allowing an operator to controllably deflect the distal portion ofdevice 50.

The distal end of outer shaft 76 includes a shaft tip 82, configured toradially expand when carrier assembly 85 is retracted. The proximal endof outer shaft 76 preferably includes a handle, not shown, but includingone or more controls, such as knobs or levers, such as to advance andretract inner shaft 78 and control shaft 84. The proximal end of device50 includes one or more connectors for connecting to an energy deliveryunit and/or a mapping unit. In an alternative embodiment, one or moreproximal control arms 86 are attached to a second control shaft suchthat the symmetry of the geometry of carrier assembly 85 can be adjustedto conform to asymmetric pulmonary vein ostia. In another alternativeembodiment, device 50 is configured to be inserted over a previouslyplaced guidewire.

Referring now to FIGS. 2 a and 2 b, the distal portion of device 50 ofFIG. 1 is illustrated. FIG. 2 a depicts carrier assembly 85 fullyexpanded, with inner shaft 78 fully advanced. FIG. 2 b depicts innershaft 78 partially retracted such that proximal arms 85 are beingcaptured and radially compressed by shaft tip 82, which expands, asshown, to create a smooth transition of carrier assembly 85 into theinner lumen of outer shaft 76.

Referring now FIG. 3, an ablation catheter of the present invention isillustrated comprising two carrier assemblies disposed serially along asingle axis, with each carrier assembly in an umbrella tipconfiguration. Ablation catheter 40 includes an elongate tube, outershaft 36, preferably constructed of Pebax material and approximately 6-8Fr in diameter, which slidingly receives first control shaft 48. Firstcontrol shaft 48 is attached on its distal portion to first carrierassembly 45, comprising multiple carrier arms and ablation elementsconfigured to deliver energy. The proximal end of first control shaft48, not shown, is attached to a control on the proximal end of ablationcatheter 40 configured to allow an operator to precisely advance andretract first control shaft 48. First control shaft 48 includes ring 52on its distal end that fixedly attaches one end of each distal carrierarm segment 44 to first control shaft 48. Each distal carrier armsegment 44 is pivotally attached on its opposite end to one end of aproximal carrier arm segment 42. The opposite end of each proximal armsegment 42 is fixedly attached to the distal end of outer shaft 36 viaring 38. Distal carrier arm segments 44 and proximal arm segments 42 areconstructed of a flexible material, such as Nitinol, and can beresiliently biased in a straight or umbrella tip configuration.Advancement and retraction of first control shaft 48 changes thediameter of carrier assembly 45, including a fully compacted (minimaldiameter) radial state when first control shaft 48 is fully advanced,and a maximum diameter state when first control shaft 48 is fullyretracted.

Fixedly mounted to distal arm segments 44 are ablation elements, RFelectrodes 46, configured to deliver energy to tissue to create lesionsfor disrupting aberrant electrical pathways in the tissue. Electrodes 46include fins 64 configured to reside in a flow of blood during energydelivery and provide sinking of heat into the circulating blood.Electrodes 46 are configured to deliver monopolar, bipolar or acombination of monopolar and bipolar RF energy as has been describedabove. Electrodes 46 preferably include integral temperature sensors,such as a thermocouple welded to an internal portion of the electrode46. Electrode 46 and any integral temperature or other sensors, areattached to wires, not shown, which travel proximally to the proximalportion of ablation catheter 40 for attachment to an energy deliveryunit, a mapping unit, and/or another electronic device for sending orreceiving signals and/or power.

First control shaft 48 slidingly receives second control shaft 57.Second control shaft 57 is attached on its distal portion to secondcarrier assembly 55, comprising multiple carrier arms and ablationelements configured to map electrical activity. The proximal end ofsecond control shaft 48, not shown, is attached to a control on theproximal end of ablation catheter 50 configured to allow an operator toprecisely advance and retract second control shaft 57. Second controlshaft 57 includes tip 62 on its distal end that fixedly attaches one endof each distal carrier arm segment 56 to second control shaft 57. Tip 62is preferably constructed of a soft or flexible material such as a softplastic or elastomer chosen to be atraumatic to tissue, and ispreferably radiopaque such as a Pebax material doped with BariumSulfate. Distal tip 62 is constructed to help navigation into andstabilization within a pulmonary vein. Distal tip 62 includes guidewirelumen 63, which is in fluid communication with an internal lumen ofsecond control shaft 57, the lumen traveling to and exiting a proximalportion of ablation catheter 40, such that ablation catheter 40 can bepercutaneously inserted into the vasculature of a patient over aguidewire.

Each distal carrier arm segment 56 is pivotally attached on its oppositeend to one end of a proximal carrier arm segment 54. The opposite end ofeach proximal arm segment 54 is fixedly attached to the distal end offirst control shaft 48 via ring 52. Distal carrier arm segments 56 andproximal arm segments 54 are constructed of a flexible material, such asNitinol, and can be resiliently biased in a straight or umbrella tipconfiguration. Advancement and retraction of second control shaft 57changes the diameter of carrier assembly 55, including a fully compacted(minimum diameter) radial state when second control shaft 57 is fullyadvanced, and a maximum diameter state when second control shaft 57 isfully retracted.

Fixedly mounted to distal arm segments 44 are ablation elements, mappingelectrodes 58, configured to map electrical activity present in tissueto target areas for creating lesions and/or otherwise assess a patientcondition. Electrodes 58 are constructed of a conductive material suchas platinum or a combination of platinum and iridium. Electrodes 58preferably include integral temperature sensors, such as a thermocouplewelded to an internal portion of the electrode 58. Electrode 58 and anyintegral temperature or other sensors, are attached to wires, not shown,which travel proximally to the proximal portion of ablation catheter 40for attachment to a mapping unit, an energy delivery unit, and/oranother electronic device for sending or receiving signals and/or power.

Ablation catheter 40 of FIG. 3 includes on its proximal end, a handle,not shown, but preferably of the type described in reference to FIG. 4and including multiple controls for allowing an operator to: advance andretract first control shaft 48; advance and retract second control shaft57; activate energy delivery to one or more of electrodes 46 or 58;operate a user interface of an energy delivery unit or mapping unit(both not shown); or perform another function. The handle includes anexit port through which a guidewire, such as a guidewire that has beenplaced into a pulmonary vein of the patient, can exit. Carrier assembly55 is sized such that it can engage the luminal wall of a pulmonaryvein, and carrier assembly 45 is sized and of sufficient flexibilitysuch that it can engage the ostium of a pulmonary vein, including anon-circular orifice. Outer shaft 36 is constructed of sufficientmaterial and the handle may be manipulated to apply conforming forces tocarrier assembly 55 and/or carrier assembly 45. Both first control shaft48 and second control shaft 57 are configured to transmit sufficienttorque to allow an operator to precisely rotationally position carrierassembly 45 and carrier assembly 55 respectively.

In an alternative embodiment, the ablation elements 46 of proximalcarrier assembly 45 may be configured to additionally or alternativelymap electrical activity in tissue. In another alternative embodiment,the ablation elements 58 of distal carrier assembly 55 may be configuredto additionally or alternatively delivery ablation energy such as RFenergy. In another alternative embodiment, the carrier arms of carrierassembly 45 and/or carrier assembly 55 may include sensors, such astemperature thermocouples, placed within an electrode or mounted to acarrier arm some distance from an electrode, such as midway between twoelectrodes. Ring 38 and Ring 52 are preferably made of a compressiblematerial, such as a metal which can be crimped in a manufacturingprocess. In an alternative or additional embodiment, adhesives may beused to fixed one or more carrier arms to a shaft. One or more adhesivesmay be used to attach distal tip 62.

Referring Now to FIG. 4, an ablation catheter of the present inventionis illustrated including the dual carrier assemblies of the ablationcatheter of FIG. 3. Ablation catheter 40 includes a tubular body member,outer shaft 36, which includes on its distal end, proximal carrierassembly 45 and distal carrier assembly 55, as have been described indetail in reference to FIG. 3. The proximal end of outer shaft 36 isattached to handle 66, which includes multiple controls: slide 67, slide68 and button 69. Slide 67 is operably attached to first control shaft48. Slide 68 is operably attached to second control shaft 57. Movementof slides 67 and 68 change the geometries of first carrier assembly 45and second carrier assembly 55 as has been described in detail inreference to FIG. 3. Numerous types of mechanical mechanisms can beincorporated into handle 66 to operably advance one or more controlshafts, such as linear slides, rotating knobs or rotating levers such asknobs connected to cam assemblies, and other mechanisms used to move theshafts forward and back. Button 69 is used to initiate energy delivery,such as when first carrier assembly 45 is positioned against a pulmonaryvein ostium and ablation catheter 40 is electrically connected to anenergy delivery unit, not shown.

Handle 60 includes two pigtails, one which terminates in luer 74 and theother which terminates with electrical connector 72. Luer 74 is in fluidcommunication with guidewire lumen 63 exiting tip 62 such that ablationcatheter 40 can be advanced over-the-wire into the vasculature of thepatient. Electrical connector 72 includes multiple connection points formultiple wires that travel within outer shaft 36 and connect to ablationelements and one or more sensors such as temperature sensors included infirst carrier assembly 45 and second carrier assembly 55. Electricalconnector 72 is configured to electrically connect to one or more of: anenergy delivery unit; a mapping unit; an electronic device for receivingand/or transmitting signals and/or power such as signals received fromtemperature or other physiologic sensors of ablation catheter 40; andcombinations of these.

Referring now to FIG. 5, an ablation catheter of the present inventionis illustrated wherein an ultrasound crystal forwardly directsultrasonic energy in a circular pattern. Ablation catheter 20 includesouter shaft 22, which slidingly receives control shaft 24, both of whichhave similar construction to the tubular body members and other shaftsdescribed throughout this application. Mounted to control shaft 24 iscarrier assembly 25, comprising proximal carrier arms 26 and distalcarrier arms 28. Proximal carrier arms 26 and distal carrier arms 28 aremade of a flexible material such as Nitinol wire and may be resilientlybiased in the geometry shown or a different geometry such as a radiallycompact geometry compatible with intravascular insertion. Each proximalcarrier arm 26 is fixedly attached at one end to control shaft 24. Eachproximal carrier arms 26 is pivotally attached at its opposite end to anend of distal carrier arms 28. The opposite end of each distal carrierarm 28 is fixedly attached, at a location more distal, to control shaft24, such that a right-angle construction is achieved. A first proximalarm 26 and attached distal arm 28 pair is attached 180° from a secondproximal arm 26 and attached distal arm 28 pair, as shown in FIG. 5. Thetwo pairs are used to contact pulmonary vein ostium 30, also as shown.Additional carrier arm pairs may be included, such as a total of fourpairs separated by 90°.

Distal to distal carrier arms 28, are centering arms 32, configured tocenter control shaft 24 in the pulmonary vein ostium and/or stabilizethe distal portion of ablation catheter 20 such as during delivery ofablation energy of mapping of electrical activity. Centering arms 32 areof similar construction to carrier arms 26 and 28, such as a round orflat Nitinol band. Alternatively or in addition to centering arms 32,the distal portion of control shaft 24 may include an inflatable balloonconfigured to center and/or anchor control shaft 24. The centeringballoon, not shown, may include one or more mapping and/or energydelivery elements. The centering and/or stabilizing elements of ablationcatheter 20, such as the centering arms 32, an inflatable balloon, orother similarly functioning element, may be integrated into the otherablation devices and catheters described throughout this application.These stabilizing and centering elements are particularly useful whenaccessing pulmonary vein ostia that are non-circular.

Fixedly mounted to centering arms 32 are mapping elements 34, electrodesconfigured to record electrical activity found in tissue. Control shaft24 includes guidewire lumen 31, which exits the distal end of controlshaft 24 and travels proximally and exits a proximal portion of ablationcatheter 20. In a preferred method, ablation catheter 20 is advancedover a previously placed guidewire that has its distal end placed into apulmonary vein of the patient.

Fixedly mounted to external shaft 24 is ultrasound crystal 21, a tubularenergy delivery element configured to deliver ultrasonic energy along acone shaped path, such as along the trajectory of proximal carrier arms26 (dashed lines shown on FIG. 5). The vector of energy delivery willcause a relatively circular patterned lesion around the pulmonary veinostium. In an alternative embodiment, the ultrasound crystal may beconfigured to provide energy in a sector (less that 360°), and thecarrier assembly 25 would be rotated and repositioned by an operatorbetween ablations to sequentially create a full circumferential lesion.

Advancement and retraction of control shaft 24 can be used to change thediameter of carrier assembly 25, such as retraction wherein the proximalportion of carrier assembly 25 is captured within the lumen of outershaft 22. Centering arms 32 are preferably connected to a control shaft,not shown, such that the centering arms can be expanded and contracted.In alternative embodiments with centering and/or stabilizing balloons,or other similar functional elements, the size of the element isconfigured to be controlled (e.g. expanded and contracted) from theproximal end of the ablation catheter.

Referring now to FIG. 6, an ablation catheter of the present inventionis illustrated wherein one or more carrier arms can be rotated along theaxis of the distal portion of the outer shaft. Ablation catheter 60includes outer shaft 96, ring 98, ring 102, carrier assembly 105, ring109 and tip 106, all of which include similar components, materials,construction and function to the same or like parts used in reference tothe ablation catheters described hereabove. Carrier assembly includesmultiple proximal carrier arms 112 which are each at one end fixedlyattached to ring 102. Proximal carrier arms 112 are each pivotallyattached at their opposite end to one end of distal carrier arms 114.The opposite end of each distal carrier arms 114 is fixedly attached tocontrol shaft 101 via ring 109, such that advancement of control shaft101 relative to outer shaft 96 causes carrier assembly 105 to changeshape. Full advancement of control shaft 101 causes carrier assembly 105to transition to a compact, minimum diameter configuration, andretraction of control shaft 101 causes carrier assembly 105 totransition to a maximum diameter configuration, such as for contactingpulmonary vein ostia.

Carrier assembly 105 further includes a rotatable arm comprising distalarm segment 108 and proximal arm segment 104. One end of distal armsegment 108 is rotatably attached to control shaft 101 via ring 109. Theopposite end of distal arm segment 108 is pivotally attached to proximalarm segment 104. The opposite end of proximal arm segment 104 is fixedlyattached to ring 98, which in turn is fixedly attached to a controlshaft, not shown but continuing proximally to a control (such as a leveror knob on a handle, both not shown) configured to allow an operator toprecisely rotate carrier arm 104.

The distal end of control shaft 101 includes tip 106, which ispreferably made of flexible material to be atraumatic to tissue. Tip 106includes a guidewire lumen 107 which continues proximally and exits aproximal portion of ablation catheter 60 such that ablation catheter 60can be percutaneously advanced over a previously placed guidewire, suchas a guidewire placed into a pulmonary vein as has been describedhereabove.

Each distal carrier arms 114 includes multiple ablation elements 116configured to deliver energy to tissue. Distal to the ablation elements116 is mapping element 118 configured to record electrical signalspresent in tissue. Distal carrier arm 108 includes multiple ablationelements 115 configured to deliver energy to tissue. Distal to theablation elements 115 is mapping element 113 configured to recordelectrical signals present in tissue. Proximal carrier arm 104 can berotated and remain concentric with the static carrier arms, such thatthe ablation elements 115 on distal arm segment 108 can be positioned ata specific distance from one or more of the ablation elements 116 onstatic distal carrier arms 114. The positioning through rotation can beused to achieve lesions of a specific length or other property,especially when bipolar energy is transmitted between ablation element115 and one or more ablation elements 116. This configuration providessimplified use in creating continuous lesions created one sector at atime. The rotation of proximal arm segment 104 and distal arm segment114 can also be performed to more properly match the contour of anon-circular pulmonary vein ostium.

In an alternative embodiment, ablation catheter 60 includes multiplerotatable carrier arms, such as carrier arms connected to independent organged control shafts such that multiple carrier arms and their integralablation element can be rotated to modify the carrier assembly geometry.

Referring now to FIG. 7, an ablation catheter is illustrated with acarrier assembly including multiple carrier arms, some of which can berepositioned relative to other carrier arms. Ablation catheter 70includes outer shaft 130, first control shaft 121, second control shaft122, carrier assembly 125 and ring 136, all of which include similarcomponents, materials, construction and function to the same or likeparts used in reference to the ablation catheters described hereabove.Carrier assembly 125 includes multiple carrier arms comprising proximalarm segments 124, 124 a and 124 b, each of which are pivotally attachedto distal arm segments 126, 126 a and 126 b respectively. Proximal armsegments 124 and distal arm segments 126, 126 a and 126 b are fixedlyattached on their opposite ends, as has been described hereabove, suchthat advancement and contraction of control shaft 121 decreases andincreases the diameter of carrier assembly 125, respectively.

Ablation catheter 70 further includes second control shaft 122 which ishollow at least on its distal portion and surround proximal arm segments124 a and 124 b such that advancement of control shaft 122 causesproximal arm segments 124 a and 124 b, each of which includes ablationelements 128 and mapping element 132, to move towards each other,changing the geometry of carrier assembly 125, similar to the geometrychange causes by rotating a carrier arm as was described in reference toFIG. 6. Both control shaft 121 and control shaft 122 are preferablyoperably connected to a control such as a knob or lever in a handle onthe proximal end of ablation catheter 70. Repositioning of one or morecarrier arms may be performed to increase or decrease the distancebetween ablation elements, mapping electrodes or other arm-mountedsensors or transducers. Repositioning of the arms may also be performedto better conform to various pulmonary vein anatomies, such as pulmonaryveins with non-circular ostia.

Ablation device 70 of FIG. 7 further includes an elongate floppy tip134, preferably of a guidewire-like construction, to assist in enteringan orifice such as a pulmonary vein lumen, or in maintaining stabilityduring a mapping or ablating procedure. In an alternative embodiment,ablation device 70 includes a guidewire lumen from a proximal portion ofthe device to a distal portion of the device.

Referring now to FIG. 8 a, an ablation catheter of the present inventionis illustrated in which multiple carrier arms are maintained in fixedpositions by a ring, such as an advancable ring. Ablation catheter 90includes outer shaft 138, control shaft 141, carrier assembly 145 andtip 154, all of which include similar components, materials,construction and function to the same or like parts used in reference tothe ablation catheters described hereabove. Carrier assembly 145includes proximal arm segments 144 which are pivotally attached todistal arm segments 146. Each distal arm segment 146 includes multipleablation electrodes 147 and a mapping sensor 148 distal to the ablationelectrodes 147. Carrier assembly 145 further includes multiple carrierarms 156, which may be void of electrodes as shown, or may include oneor more mapping or ablating electrodes, or other sensor or transducer.

Referring also to FIG. 8 c, each proximal carrier arm segment iscircumferentially positioned in a groove 246 of ring 142. Carrier arms156 are similarly positioned in a groove 256 of ring 142. Ring 142 ispreferably attached to a control shaft, not shown, such that advancementof that control shaft changes the geometry of carrier assembly 145accordingly. Retraction of control shaft 141 changes the diameter ofcarrier assembly 145 as has been described in detail hereabove. FIG. 8 billustrates an end view of the ablation catheter 90 of FIG. 8 a, showingthe rotational orientation of the distal arm segments 146 and carrierarms 156. Carrier arms 156 are positioned orthogonal to two sets ofthree distal carrier arms 146 such as to provide positioning and radialsupport to distal carrier arms 146. Various configurations of carrierarm geometries can be provided for handling of various pulmonary veintissue contours. Ring 142 may maintain the ablation elements 147 and/orthe mapping elements 148 in close proximity.

In an alternative embodiment, ring 142 is not advancable (not connectedto a control shaft), but included with grooves 256 and grooves 246 tomaintain the rotational orientation of the distal carrier arms 146 andthe carrier arms 156 such as when force is applied to outer shaft 138,such as via a handle, the force translated to carrier assembly 145.

Referring now to FIG. 9, an ablation catheter of the present inventionis illustrated in which an advancable spline can be radially expanded toimprove or otherwise alter the structure and rigidity of a carrierassembly. Ablation catheter 90 b includes outer shaft 138, control shaft141, carrier assembly 95 and tip 154, all of which include similarcomponents, materials, construction and function to the same or likeparts used in reference to the ablation catheters described hereabove.Carrier assembly 95 includes multiple carrier arms 156 in an umbrellatip configuration, one or more including ablation elements, othersensors or transducers, all not shown. As control shaft 141 is advancedand retracted (e.g. via a control on a proximal handle, both not shown),carrier assembly 95 contracts and expands respectively, as has beendescribed hereabove. Control shaft 141 slidingly receives an advancablespline 164, whose distal end resides in recess 162 of control shaft 141.Advancement of spline 164 causes its distal end to extend radially outfrom control shaft 141 as is shown in FIG. 9 a (partially extended) andFIG. 9 b (fully extended). In a preferred embodiment, spline 164 can beadvanced to the maximum diameter of carrier arms 156. In an alternativeembodiment, spline 164 can be advanced to a diameter greater than themaximum diameter of carrier arms 156. Spline 164 is advance to modifythe performance characteristics of carrier assembly 95, such as tomodify the supporting forces applied to tissue. In an alternativeembodiment, spline 164 includes one or more ablation elements (e.g. RFelectrodes) or other sensors or transducers.

Referring now to FIGS. 10 and 11, an ablation catheter of the presentinvention is illustrated in which the carrier assembly comprises aninflatable balloon with multiple ablation elements mounted on orembedded in its external surface. Ablation catheter 100 includes carrierassembly 175 comprising balloon 174 and electrodes 172, such as RFablation or electrical signal mapping electrodes. Ablation catheter 100further includes an elongate tubular body, outer shaft 166, whichincludes an inflation lumen 176 from its proximal portion to the innercavity of balloon 174. Balloon 174 is sealed and fixedly attached to thedistal portion of outer shaft 166. Passage of fluid such as air orsaline through the inflation lumen of outer shaft 166 causes balloon 174to inflate and remain in an expanded state as long as the fluid pressureis maintained. Balloon 174 may be a compliant or non-compliant balloon,and while shown as a disk or donut shape, may have profiles specific tomimic pulmonary vein ostia and the tissue extending therefrom.

Extending from the distal end of and coaxial to external shaft 166 iscentering post 168 which traverses from the proximal end to the distalend of balloon 174, and includes a projection configured to engage apulmonary vein lumen. In a preferred embodiment, a guidewire lumen isincluded from the distal end to a proximal portion of ablation catheter100 such that ablation catheter may be advanced over a guidewire such asa guidewire that has previously been placed into a pulmonary vein ostiumor other applicable orifice. Mapping and/or ablating procedures can beaccomplished by an operator applying a force to balloon 174 via shaft166, and transmitting ablation energy to electrodes 172 and/or recordingelectrical activity from electrodes 172.

Referring now to FIG. 12 a, ablation catheter of the present inventionis illustrated in which the carrier assembly includes a single carrierarm that can be positioned into an adjustable, partial circumferential(less than 360°) loop for ablating and/or mapping tissue. Ablationdevice 180 includes an elongate tubular body member, outer shaft 182,with sufficient column and torsion strength to support standardinterventional procedures such as those which access the vasculaturefrom a femoral vein or artery and access the patient's heart. Outershaft 182 is constructed of biocompatible materials such as Pebax, andpreferably includes an inner braid, such as a stainless steel 304 braid.The proximal portion of outer shaft 182 is preferably made of Pebax7233D and the distal portion of outer shaft 182 is preferably made ofPebax 55/3533D. Outer shaft 182 is fixedly attached to handle 195 viastrain relief 181.

Exiting the distal end of outer shaft 182 are control shaft 184 andcarrier assembly 185, which comprises a single carrier arm 186. At leastone of control shaft 184 and carrier arm 186 can be advanced and/orretracted by manipulating a control on handle 195, such as rotating knob193. In a preferred embodiment, the proximal end of carrier arm 186 isfixedly attached to a distal portion of outer shaft 182, such as via acrimp and/or adhesives, and outer shaft 184 is slidingly received byouter shaft 182 and operably attached to rotating knob 193. Carrier arm185, preferably made of an elastic material such as Nitinol covered witha sleeve made of Pebax, includes one or more electrodes 188 along itslength. The electrodes 188 may include heat-sinking fins as shown. Theelectrodes 188 are preferably made of platinum, and are typically 3 mmlong and separated by 1 to 4 mm, with symmetric or asymmetric spacing.Four electrodes 188 are depicted in FIGS. 12 a through 12 c. Four (4) tosixteen (16) electrodes 188 are preferred, typically eight (8) to ten(10). The presence of multiple, typically uniformly distributedelectrodes enables the operator to rapidly identify problematic targetareas (undesired electrical activity) and create lesions (ablate)rapidly. The multi-electrode geometry of carrier assembly 185, precisionloop control, and ease of positioning (including over-the-wirepositioning and anchoring), enables simplified, customized diagnosis andtreatment of heart rhythm disorders such as atrial fibrillation.

Electrodes 188 may be for delivering of ablation energy, for mapping ofelectrical activity, and/or for performing other functions such aspacing of the heart. Alternatively or additionally, carrier arm 185 mayinclude different types of sensors and/or transducers, such as sensorsor transducers that can be applied to the ostium of a vessel to performa diagnostic and/or therapeutic function. The distal end of carrier arm185 is fixedly attached to the distal end of control shaft 184, theconnection point encased by tip 192. Tip 192 is of materials andconstruction to be atraumatic, such as a Pebax tip, which has been dopedwith Barium Sulfate in order to be radiopaque. Tip 192 includesguidewire lumen 191, a through hole which travels proximally, throughcontrol shaft 184, and exits handle 195 at guidewire exit hole 199,configured such that ablation device 180 can be percutaneously advancedover a guidewire which has had its distal end inserted into a pulmonaryvein of the patient.

Handle 195, preferably made of a plastic such as a polycarbonate,includes lever 196 which is operably attached to one or more pull wires,not shown, that travel within a lumen of outer shaft 182 and attach nearthe distal end of shaft 182. Multiple pull wires may be included, suchas two pull wires which are attached at a 90° radial separation fromeach other near the distal end of shaft 182. The two pull wires may beattached at the same longitudinal position along the axis of shaft 182,or may be offset. Manipulation of lever 196 causes the distal portion ofablation catheter 180 to deflect in one or more planes such that aclinician can manipulate tip 192 into a pulmonary vein or other orificesuch as the coronary sinus or other vessel.

Handle 195 also includes plug 198 which is configured to electricallyconnect to one or more separate devices, such as an energy delivery unitconfigured to deliver ablation energy to electrodes 188 and/or toreceive temperature signals from one or more temperature sensors such asa thermocouple integral to an electrode 188; a mapping unit configuredto receive electrical signals from one or more electrodes 188; a pacingunit configured to deliver electrical energy to electrodes 188 in orderto pace the heart of a patient; or another device such as a device whichreceives and/or transmits signals to one or more functional elements ofcarrier assembly 185. Wires, not shown, attach to plug 198 and travelthrough handle 195, through outer shaft 182 and attach to electrodes 188and any other sensors or transducers integral to electrodes 188 orattached to carrier arm 186. The wires may be located on the externalsurface of carrier arm 186, or travel within a lumen of carrier arm 186,exiting through a side hole to attach to electrodes 188.

Referring additionally to FIG. 12 b, carrier assembly 185 is shown in alinear configuration such that ablation device 180 can be intraluminallyadvanced through the vasculature of the patient. Carrier assembly 185 isplaced in this linear configuration by advancing control shaft 184 suchas via rotating knob 193 of handle 195. Referring now to FIG. 12 c,control shaft 184 is being retracted, and carrier assembly 185 istransitioning to a partial circumferential (less than 360°) loop.Advancement and retraction of control shaft 184 adjust the geometry ofthe loop, wherein full advancement causes a near-linear configurationand retraction causes the diameter of carrier assembly 185 to increase.Preferred maximum diameters of carrier assembly 185 are typically 15-32mm to accommodate the varied anatomical contours neighboring pulmonaryvein ostia (including non-circular ostia). The simplified loop-modifyingcontrols of the present invention allow for rapid positioning by anoperator. In a preferred embodiment, carrier arm 186 is resilientlybiased (such as with the heat treating of a Nitinol component) in ahelical configuration. In an alternative embodiment, carrier arm 186 isresiliently biased in a near-linear configuration. In the configurationwhere carrier arm 186 includes a wire surrounded by a sleeve, aresilient bias can be provided by the wire or the sleeve.

In another alternative embodiment, the proximal end of carrier arm 186exits outer shaft 182 at a location approximate 90° radially offset fromthe location that carrier arm 186 is attached to the distal end ofcontrol shaft 184, such offset attachment providing a bias for formingthe loop during retraction of control shaft 184.

Carrier assembly 185 may include a loop of 360° or more. In anotheralternative embodiment, outer shaft 182 may include a mechanical key tomaintain the rotational orientation of control shaft 184 and/or carrierarm 186. Control shaft 184 may include an attachment ring near itsdistal end such as for attachment to the proximal end of carrier arm186. In another preferred embodiment, carrier assembly 185 includes atleast one temperature sensor more distal than the most distal ablationelement delivering ablation energy, such that the maximum distal (e.g.into the pulmonary vein lumen) temperature is always monitored (e.g. toprevent creation of a pulmonary vein stenosis). In the configuration ofFIGS. 12 a through 12 c, both control shaft 184 and carrier arm 186 exitthe distal end of outer shaft 182. In an alternative embodiment, eitheror both control shaft 184 or carrier arm 186 exit a side hole of outershaft 182 (not shown but near the distal end of outer shaft 182). Inanother alternative embodiment, control shaft 184 may be rotated, suchas via a control on handle 195, to further change the geometry ofcarrier assembly 185.

Referring now to FIGS. 13, 13 a and 13 b, the ablation catheter of FIG.12 a is illustrated. In FIG. 13, ablation catheter 180 is shown withcarrier assembly 185 in linear configuration such as for advancingablation catheter 180 over guidewire 12, such as an intraluminaladvancement over a guidewire which has been inserted into a femoralvein, and travels to the heart, through the septum separating the rightatrium and left atrium (e.g. through a transeptal sheath), and into apulmonary vein such as the left superior pulmonary vein. Carrierassembly 185 is placed in this linear, maximally compact configurationby advancing control shaft 184, such as by manipulating a control on ahandle of device 180 as has been described hereabove. Carrier arm 186includes electrodes 188. Carrier arm 186 has a proximal end fixedlyattached to outer shaft 182 via crimp ring 194. Carrier arm 186 distalend is fixedly attached to control shaft 184 at a radial location thatis 90° offset from its proximal end attachment (as shown in FIG. 13),such that carrier assembly 185 radially expands as shown in FIGS. 13 aand 13 b as control shaft 184 is retracted. The distal end of controlshaft 184 is covered with atraumatic tip 192, which includes an exithole in communication with an internal guidewire lumen, not shown butthrough which guidewire 12 passes.

Referring now to FIG. 14, a preferred construction of the ablationcatheter of FIG. 12 a is illustrated. Ablation catheter 180 includescarrier assembly 186, which comprises a single carrier arm 186 whosegeometry is adjusted by advancing and retracting control shaft 184, ashas been described in detail hereabove. Carrier arm 186 includes wireshaft 202, preferably Nitinol or other shaped memory alloy or polymer,surrounded by outer sleeve 203, preferably Pebax or other biocompatible,soft material. Sleeve 203 can perform one or more functions, includingbut not limited to: capturing one or more wires between wire 202 andsleeve 203; acting as an insulator; providing an atraumatic boundary(e.g. covering any sharp edges of wire 202); and combinations thereof.Wire shaft 202 preferably is resiliently biased in the loop geometrydepicted. The proximal end of carrier arm 186 is fixedly attached toouter shaft 182 via ring 194. Alternatively or additionally, adhesivessuch as cyanoacrylate may be used for fixation. In an alternativeembodiment, ring 194 also functions as an electrode, such as a mappingand/or ablation electrode.

At its distal end, carrier arm 186 is fixedly attached to cap 192 andthe distal end of control shaft 184. Cap 192 is of soft construction tobe atraumatic to tissue, and is preferably made of Pebax which has beendoped with Barium Sulfate to be radiopaque. A guidewire lumen 201 exitscap 192 after having passed within control shaft 184. Guidewire lumen201 is surrounded by a braided tube preferably made of Nylon and braidedwith stainless steel wire. The guidewire lumen 201 travels proximally toan exit port on a handle, not shown but described in detail hereabove.

Electrodes 188 are fixedly mounted to carrier arm 186, such as withcyanoacrylate (or other adhesive) beads 204. Each electrode 188preferably includes a thermocouple, not shown but preferably acopper-constantan wire junction welded to an internal surface ofelectrode 188. Each electrode, and any included thermocouple, isattached to one or more wires (attachment not shown), which are groupedwith other wires to form wire bundle 210, which travels proximally andis attached to an electrical port on the proximal end of ablationcatheter 180. Carrier arm 184 may include other sensors or transducers,some of which may also be attached to wires included in wire bundle 210,these sensors or transducers placed against tissue such as pulmonaryvein ostial tissue to perform a diagnostic or therapeutic procedure in apatient.

FIG. 14 further illustrates a preferred construction of the distalportion of outer shaft 182. Immediately proximal to ring 194 is distalsegment 205, preferably made of Pebax 5533 or 6333. Immediately proximalto distal segment 205 is hinge segment 206, and proximal to hingesegment 206 is wall 212. Hinge segment 206 is preferably made of asoftware material than distal segment 205 and wall 212, such as Pebax3533. Mounted within hinge segment 206 is second anchor ring 211, ametal (e.g. stainless steel) ring that is fixedly attached to two (2)pull wires 209. Pull wires 209 extend proximally and are attached to aknob, lever or other control integral to a handle, all not shown butoperably configured to deflect the distal end of ablation catheter 180in multiple planes. Wall 212 surrounds braid 207 and braid 207 surroundsliner 208. Braid 207, a standard catheter braid to provide column andtorsion support, is preferably made of stainless steel such as 304stainless steel. Liner 208 is preferably made of Teflon or anotherlubricious material that allows one or more shafts, such as controlshaft 184 and pull wires 209, to be slidingly received within a lumen ofshaft 182 without significant resistance.

Referring now to FIGS. 15 a through 15 d, the ablation catheter of FIG.12 a is illustrated. Ablation catheter 180 includes outer shaft 182,control shaft 184, ring 194, carrier assembly 185 and tip 192, all ofwhich include similar components, materials, construction and functionto the same or like parts used in reference to the ablation cathetersdescribed hereabove. FIG. 15 a illustrates the proximal portion,including handle, preferably made of a plastic such as polycarbonate.Handle 195 includes lever 196 and slide 197, controls used by anoperator to adjust the carrier assembly, deflect the distal portion ofcatheter 180 and/or perform other functions. Handle 195 is fixedlyattached to shaft 182. Extending from handle 195 is pigtail plus 198, anelectrical connector that attaches signal and power wires to one or morecomponents of ablation catheter 180 such as ablation electrodes, mappingelectrodes and thermocouples.

Referring now to FIG. 15 b, the distal end of catheter 180 isillustrated including the distal end of outer shaft 182. FIG. 15 billustrates carrier assembly 185 in its compacted, linear configurationapplicable for over-the-wire intraluminal advancement of ablationcatheter 180, such as to reach the left superior pulmonary vein asdepicted in FIG. 15 d. Referring back to FIG. 15 b, control shaft 184has been fully advanced such that carrier arm 186 is pulled tightagainst control shaft 184. Control shaft 184 includes on its distal endtip 192. Within tip 192 is guidewire lumen 191 through which a standardinterventional guidewire, such as a 0.035″ guidewire, can be inserted.Carrier arm 185 is configured, as has been described in detailhereabove, such that upon retraction of control shaft 184, carrier arm186 extends laterally into the loop configuration illustrated in FIG. 15c.

Referring additionally to FIG. 15 d, the treatment to be accomplishedwith the devices and method described in this application isillustrated. FIG. 15 d shows a cutaway view of the human heart 10,showing the major structures of the heart including the left and rightatria, and the pulmonary veins 15. The atrial septum separates the leftand right atria. The fossa ovalis is a small depression in the atrialseptum that may be used as an access pathway to the left atrium from theright atrium, such as with a transeptal puncture device and transeptalsheath. The fossa ovalis can be punctured, and easily reseals and healsafter procedure completion. In a patient suffering from atrialfibrillation, aberrant electrically conducive tissue may be found in theatrial walls, as well as in the pulmonary veins 15. Ablation of theseareas, referred to arrhythmogenic foci (also referred to as drivers orrotors), is an effective treatment for atrial fibrillation. Thecatheters of the present invention provide means of creating lesions,including lesions to surround the pulmonary vein ostia, and are easilydeployed to identify and ablate the driver and rotor tissue.

To accomplish this, catheter 180 is inserted into the right atrium,preferably through the inferior vena cava, as shown in the illustration,or through the superior vena cava. Catheter 180 is sized for thisadvancement through the patient's vasculature, such as where theinserted (shaft) diameter is approximately 9 Fr, the shaft length isapproximately 115 cm and the overall length is typically 158 cm.Catheter 180 has been passed through transeptal sheath 11, which may ormay not be a deflectable sheath since catheter 180 preferably includes adeflectable distal portion. When passing into the left atrium,transeptal sheath 11 passes through or penetrates the fossa ovalis, suchas over guidewire 12 which may have been placed by a transeptal puncturedevice. Catheter 180 is inserted over guidewire 12 and throughtranseptal sheath 11 such that its distal end enters right superiorpulmonary vein 15's lumen. The distal portion of shaft 182 has beendeflected such that the distal end of shaft 182 is directed toward thelumen of pulmonary vein 15 a. Catheter 180 carries a structure carryingmultiple ablation elements such as RF electrodes, carrier assembly 185,into the left atrium. Carrier assembly 185 has been transitioned toexpand to a maximal diameter by retracting control shaft 184, such thatmultiple ablation elements (ablation and/or mapping elements),electrodes 188, are in contact with the pulmonary vein ostial tissue.Carrier assembly 185 is adapted to be deformable such that pressingcarrier assembly into pulmonary vein 15 ostium will cause one or more,and preferably all of electrodes 188 to make contact with tissue to beanalyzed and/or ablated. Each of the electrodes 188 is attached viaconnecting wires and one or more connectors, such as plug 198, to anenergy delivery apparatus, not shown but preferably an RF energydelivery unit which is also attached to a patch electrode, also notshown but preferably a conductive pad attached to the back of thepatient.

The energy delivery unit is configured to delivery RF energy inmonopolar, bipolar or combination monopolar-bipolar energy deliverymodes, simultaneously or sequentially, with or without “off” or noenergy delivered time durations. In a preferred embodiment, the energydelivery unit 200 is configured to also provide electrical mapping ofthe tissue that is contacted by one or more electrodes integral tocarrier assembly 185. Alternatively, a separate mapping unit may beused, preferably attached to catheter 180 simultaneous with attachmentto the energy delivery unit. Electrodes 188 can also be configured to bemapping electrodes and/or additional electrodes can be integral tocarrier assembly 185 to provide a mapping function. Carrier assembly 185is configured to be engaged over a pulmonary vein ostium surface to mapand/or ablate tissue on the surface. Energy is delivered after a properlocation of the electrodes 188 is confirmed with a mapping procedure. Ifconditions are determined to be inadequate, an operator may adjust theshape of carrier assembly 185 (e.g. through advancement or retraction ofcontrol shaft 184) and/or the operator may reposition carrier assembly185 against tissue through various manipulations at the proximal end ofthe ablation catheter 180. After an ablation step is completed, ablationcatheter 180 is repositioned, with or without changing the geometry ofcarrier assembly 185, and a similar mapping and ablation step isperformed. For each pulmonary vein ostium, this repositioning willtypically occur two to three times creating semi-circular lesions thatpreferably overlap. The steerability of the distal portion of shaft 182,via a control on handle 195, is an important function in thisrepositioning process. In a typical procedure, the clinician willperform ablations in the left superior pulmonary vein first, followed bythe right superior, left inferior and then the right inferior pulmonaryveins.

In a preferred embodiment, the energy delivery unit is configured todelivery both RF energy and ultrasound energy to the identical ordifferent electrodes 188. In another preferred embodiment, the energydelivery unit is configured to accept a signal from one or more sensorsintegral to ablation catheter 180, not shown, such that the energydelivered can be modified via an algorithm which processes theinformation received from the one or more sensors.

In an alternative embodiment, a guidewire is inserted through a sidecarpresent at the distal portion of shaft 182, avoiding the need forthreading the entire the device over the guidewire. In anotheralternative embodiment, carrier arm 186 is attached to a second controlshaft, also slidingly received by outer shaft 182 and connected to acontrol on handle 195, such that the carrier assembly 185 geometry canbe adjusted by advancing and retracting either the second control shaftor control shaft 184. This dual control shaft design also allows carrierassembly to be completely retracted within the distal end of controlshaft 182, as is described in reference to FIG. 17 herebelow.

Referring now to FIG. 16, an ablation catheter of the present inventionis illustrated comprising a first deployable carrier assembly includingmultiple ablation electrodes and a more distal second deployable carrierassembly including multiple mapping electrodes. Ablation catheter 400includes outer shaft 410, first control shaft 411, second control shaft412, first carrier assembly 430 a, second carrier assembly 430 b and tip415, all of which include similar components, materials, constructionand function to the same or like parts used in reference to the ablationcatheters described hereabove. Outer shaft 410, preferably a braidedconstruction including braid 413, slidingly receives first control shaft410, which in turn slidingly receives second control shaft 411. Outershaft 410 is fixedly attached to handle 420 via strain relief 426. Anatraumatic tip 415 is fixedly attached to the distal end of secondcontrol shaft 412. A guidewire lumen 416 exits tip 415 and travelsproximally, through second control shaft 412, first control shaft 411and outer shaft 410 to handle 420 where it exits via guidewire entry424, such that ablation catheter 400 can be percutaneously introducedinto a patient over a previously placed guidewire.

First carrier assembly 430 a comprises a single carrier arm, firstcarrier arm 433, which is fixedly attached on its distal end to thedistal end of first control shaft 411 and on its proximal end to thedistal end of outer shaft 410. First control shaft 411 is operablyconnected on its proximal end to first advancable knob 421, such thatadvancement and retraction of knob 421 causes advancement and retractionof first control shaft 411. Advancement and retraction of first controlshaft 411 causes first carrier assembly 430 a to contract and expand,respectively, as has been described hereabove. Full advancement of firstcontrol shaft 411 causes first carrier assembly 430 a to have a minimumdiameter (fully constrained near-linear configuration) and fullretraction of control shaft 411 causes first carrier assembly 430 a tohave a maximum diameter. First carrier assembly 430 a includeselectrodes 431, and each electrode 431 is preferably at least configuredto deliver ablation energy to tissue.

Second carrier assembly 430 b comprises a single carrier arm, secondcarrier arm 434, which is fixedly attached on its distal end to thedistal end of second control shaft 412 and on its proximal end to thedistal end of first control shaft 411. Second control shaft 412 isoperably connected on its proximal end to second advancable knob 422,such that advancement and retraction of knob 422 causes advancement andretraction of second control shaft 412. Advancement and retraction offirst control shaft 411 (via advancement and retraction of knob 421)causes second carrier assembly 430 b to expand and contract,respectively. Also, advancement and retraction of second control shaft412 (via advancement and retraction of knob 422) causes second carrierassembly 430 b to contract and expand, respectively, as has beendescribed hereabove. Advancement and retraction of first control shaft411 and second control shaft 412, in combination or independently,changes the geometry of second carrier assembly 430 b accordingly. Forintraluminal advancement of ablation catheter 400, both first carrierassembly 430 a and second carrier assembly 430 b are placed in a minimaldiameter configuration. Second carrier assembly 430 b includeselectrodes 432, and each electrode 432 is preferably at least configuredto record electrical activity present in tissue. Electrodes 431 andelectrodes 432 preferably include an integral temperature sensor, suchas a thermocouple constructed of a copper-constantan bimetallicassembly. Electrodes 431 may be further configured to record electricalsignals in tissue and electrodes 432 may be further configured todeliver ablation energy to tissue.

Handle 420 also includes lever 423, which is operably attached to one ormore pull wires which extend distally within a lumen, such as a Teflonlined lumen, within outer shaft 410. The one or more pull wires arefixedly attached to a distal portion of outer shaft 410 causing operatorcontrolled deflection of the distal portion of ablation catheter 400 inone or more planes. Handle 420 further includes electrical plug 425which is electrically connected to one or more electrical wires or otherconduits, all of which travel distally, along outer shaft 410 to variouslocations such as electrodes 431 or electrodes 432, or another sensor ortransducer not shown. Plug 425 is configured to attach to an energydelivery unit such as an RF energy delivery unit, a mapping unit oranother device configured to transmit or receive electrical signals orpower.

FIG. 16 a illustrates an end view of the ablation catheter of FIG. 16.First carrier assembly 430 a and second carrier assembly 430 b are bothin their maximum diameter configurations. FIG. 16 b illustrates a sideview of the ablation catheter of FIGS. 16 and 16 a inserted into avessel, such as a pulmonary vein 15, through its ostium. Second carrierassembly 430 b is partially or fully expanded and in contact with theluminal wall of vein 15. First carrier assembly 430 a is partially orfully expanded and engaging the ostium of vein 15.

Referring now to FIGS. 17, 17 a, 17 b and 17 c, an ablation catheter ofthe present invention is illustrated. Ablation catheter 180 b is ofsimilar construction to ablation catheter 180 of FIGS. 12 through 14with common elements having the same reference numbers. For brevity,most of the common construction and common component details will beomitted. Ablation catheter 180 b includes handle 195 with operatorcontrols first slide 197 a, second slide 197 b and lever 196, eachoperably attached to a control shaft or other linkage. Plug 198 isconnected to one or more electrical wires or other conduits that traveldistally through outer shaft 182 and connect to one or more functionalelements of the device, such as electrodes included in carrier assembly185. The distal end of ablation catheter 192 includes an atraumatic tip192, preferably constructed of Pebax which has been doped with BariumSulfate for radiopacity. The ablation catheter 180 b of FIG. 17 depictsthe carrier assembly 185 in a fully deployed (maximum diameter)configuration, caused by retracting the control shaft via a slide orlever on handle 196.

Referring now to FIG. 17 a, carrier arm carrier assembly 185 is in itsfully deployed (maximum diameter) condition. Carrier arm 186 is attachedon its distal end to first control shaft 182. On its proximal end,instead of being attached to the distal portion of outer shaft 182 asthe ablation device 180 of FIG. 12 a, carrier arm 186 is attached to asecond control shaft 213, which also can be advanced and retracted froma control on handle 195. Advancement and retraction of both firstcontrol shaft 184 and second control shaft 213 can be used,independently or in combination, to change the geometry of carrierassembly 185.

Referring now to FIG. 17 b, a differentiating feature of ablationcatheter 180 b is illustrated where second control shaft 213 has beenretracted until carrier arm 186, including ablation elements 188, iscontained completely within a lumen of outer shaft 182, such as within alumen within a Teflon liner. In an alternative embodiment, carrier arm186 is retracted within outer shaft 182 by retracted first control shaft184.

Referring now to FIG. 17 c, an end view of the device and deploymentstatus of FIG. 17 a is illustrated. Carrier arm 186 is shown in its lessthan 360° helix. Also shown are electrodes 188, typically 2-3 mm inlength with symmetric 3 mm spacing between electrodes.

It should be understood that numerous other configurations of thesystems, devices and methods described herein can be employed withoutdeparting from the spirit or scope of this application. It should beunderstood that the system includes multiple functional components, suchas the ablation catheter and the energy delivery apparatus. The ablationcatheter consists of a catheter shaft, a carrier assembly for providingelectrodes in a resiliently biased configuration, a control shaft fordeploying and withdrawing the carrier assembly, and a coupler forattaching the control shaft to the carrier assembly. The carrierassembly is a support structure which is shiftable from a storage orconfined configuration, such as a radially constrained configuration, toa deployed or expanded configuration. The carrier assembly can includeswires, ribbons, cables and struts, made of either metals, non-metals orcombinations of both. The carrier assembly can be constructed of one ormore materials, including both metals and non-metals. Typical metalschosen for carrier assembly construction include but are not limited to:stainless steel, Nitinol, Elgiloy™, other alloys and combinationsthereof.

The ablation catheter of the present invention may include a steerableouter sheath, or may work in conjunction as a system with a separatesteerable outer sheath. One or more tubular components of the ablationcatheter may be steerable such as with the inclusion of a controllablepull wire at or near the distal end. The ablation catheter of thepresent invention may be inserted over the wire, such as via a lumenwithin one of the tubular conduits such as within a lumen of the tubularbody member or control shaft, or alternatively the catheter may includea rapid exchange sidecar at or near its distal end, consisting of asmall projection with a guidewire lumen therethrough. A guidewire lumenmay be included solely for the guidewire, or may provide other functionssuch as a vacuum lumen for an integral suction port integrated at thedistal portion of the carrier assembly.

The ablation catheter of the present invention further includes ablationelements. In preferred embodiments, one or more ablation elements areelectrodes configured to deliver RF energy. Other forms of energy,alternative or in addition to RF, may be delivered, including but notlimited to: acoustic energy and ultrasound energy; electromagneticenergy such as electrical, magnetic, microwave and radiofrequencyenergies; thermal energy such as heat and cryogenic energies; chemicalenergy; light energy such as infrared and visible light energies;mechanical energy; radiation; and combinations thereof. One or moreablation elements may comprise a drug delivery pump or a device to causemechanical tissue damage such as a forwardly advanceable spike orneedle. The ablation elements can deliver energy individually, incombination with or in serial fashion with other ablation elements. Theablation elements can be electrically connected in parallel, in series,individually, or combinations thereof. The ablation catheter may includecooling means to prevent undesired tissue damage and/or blood clotting.The ablation elements may be constructed of various materials, such asplates of metal and coils of wire for RF energy delivery. The electrodescan take on various shapes including shapes used to focus energy such asa horn shape to focus sound energy, and shapes to assist in cooling suchas a geometry providing large surface area. Electrodes can vary within asingle carrier assembly, such as a spiral array of electrodes or aumbrella tip configuration wherein electrodes farthest from the centralaxis of the catheter have the largest major axis. Wires and otherflexible conduits are attached to the ablation elements, such aselectrical energy carrying wires for RF electrodes or ultrasoundcrystals, and tubes for cryogenic delivery.

The ablation elements requiring electrical energy to ablate requirewired connections to an electrical energy power source such as an RFpower source. In configurations with large numbers of electrodes,individual pairs of wires for each electrode may be bulky and compromisethe cross-sectional profile of the ablation catheter. In an alternativeembodiment, one or more electrodes, connected in serial fashion suchthat a reduced number of wires, such as two wires, can be attached totwo or more electrodes, include switching means such that while a firstelectrode is powered, the remaining electrodes do not transmit ablativeenergy. Switching means may be a thermal switch, such that as a firstelectrodes heats up, a single pole double throw switch change statedisconnecting power from that electrode and attaching power to the nextelectrode in the serial connection. This integral temperature switch mayhave a first temperature to disconnect the electrode, and a secondtemperature to reconnect the electrode wherein the second temperature islower than the first temperature, such as a second temperature belowbody temperature. In an alternative embodiment, each electrode isconstructed of materials in their conductive path such that as when thetemperature increased and reached a predetermined threshold, theresistance abruptly decreased to near zero, such that power dissipation,or heat, generated by the electrode was also near zero, and more powercould be delivered to the next electrode incorporating the aboveswitching means.

The ablation catheter of the present invention preferably includes ahandle activating or otherwise controlling one or more functions of theablation catheter. The handle may include various knobs, such asrotating or sliding knobs which are operably connected to advanceableconduits, or are operably connected to gear trains or cams which areconnected to advanceable conduits. These knobs, such as knobs use todeflect a distal portion of a conduit, or to advance or retract thecarrier assembly, preferably include a reversible locking mechanism suchthat a particular tip deflection or deployment amount can be maintainedthrough various manipulations of the system.

The ablation catheter may include one or more sensors, such as sensorsused to detect chemical activity; light; electrical activity; pH;temperature; pressure; fluid flow or another physiologic parameter.These sensors can be used to map electrical activity, measuretemperature, or gather other information that may be used to modify theablation procedure. In a preferred embodiment, one or more sensors, suchas a mapping electrode, can also be used to ablate tissue.

Numerous components internal to the patient, such as the carrierassembly or electrodes, may include one or more visual markers such asradiopaque markers visible under fluoroscopy, or ultrasound markers.

Selection of the tissue to be ablated may be based on a diagnosis ofaberrant conduit or conduits, or based on anatomical location. RF energymay be delivered first, followed by another energy type in the samelocation, such as when a single electrode can deliver more than one typeof energy, such as RF and ultrasound energy. Alternatively oradditionally, a first procedure may be performed utilizing one type ofenergy, followed by a second procedure utilizing a different form ofenergy. The second procedure may be performed shortly after the firstprocedure, such as within four hours, or at a later date such as greaterthan twenty-four hours after the first procedure. Numerous types oftissue can be ablated utilizing the devices, systems and methods of thepresent invention. For example, the various aspects of the inventionhave application in procedures for ablating tissue in the prostrate,brain, gall bladder, uterus, other organs and regions of the body, and atumor, preferably regions with an accessible wall or flat tissuesurface. In the preferred embodiment, heart tissue is ablated, such asleft atrial tissue.

In another preferred embodiment of the system of the present invention,an ablation catheter and a heat sensing technology are included. Theheat sensing technology, includes sensor means that may be placed on thechest of the patient, the esophagus or another area in close enoughproximity to the tissue being ablated to directly measure temperatureeffects of the ablation, such as via a temperature sensor, or indirectlysuch as through the use of an infrared camera. In the described system,when a temperature or a surrogate temperature reaches a threshold, suchas an adjustable threshold, the ablation energy is reduced or stopped,to one or more ablation elements. The threshold will depend on thelocation of the sensor means, as well as where the ablation energy isbeing delivered. The threshold may be adjustable, and may beautomatically configured.

Numerous kit configurations are also to be considered within the scopeof this application. An ablation catheter is provided with multiplecarrier assemblies. These carrier assemblies can be removed for thetubular body member of the catheter, or may include multiple tubularbody members in the kit. The multiple carrier assemblies can havedifferent patterns, different types or amounts of electrodes, and havenumerous other configurations including compatibility with differentforms of energy.

Though the ablation device has been described in terms of its preferredendocardial and transcutaneous method of use, the array may be used onthe heart during open heart surgery, open chest surgery, or minimallyinvasive thoracic surgery. Thus, during open chest surgery, a shortcatheter or cannula carrying the carrier assembly and its electrodes maybe inserted into the heart, such as through the left atrial appendage oran incision in the atrium wall, to apply the electrodes to the tissue tobe ablated. Also, the carrier assembly and its electrodes may be appliedto the epicardial surface of the atrium or other areas of the heart todetect and/or ablate arrhythmogenic foci from outside the heart.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims. In addition,where this application has listed the steps of a method or procedure ina specific order, it may be possible, or even expedient in certaincircumstances, to change the order in which some steps are performed,and it is intended that the particular steps of the method or procedureclaim set forth herebelow not be construed as being order-specificunless such order specificity is expressly stated in the claim.

1. A device as described in reference to the drawings.
 2. A method asdescribed in reference to the drawings.
 3. An ablation cathetercomprising: a) an elongated, flexible, tubular body member having aproximal end, a distal end and a lumen extending therebetween; b) acontrol shaft coaxially disposed and slidingly received within the lumenof the Tubular Body Member; c) a flexible carrier assembly whichincludes at least one ablation or mapping element that is adjustablefrom a near linear configuration to a partial helix by advancement orretraction of the control shaft.